This invention generally relates to a method and apparatus for treating and disinfecting water and/or wastewater which also comprises generating various chlorine containing compounds, e.g. chlorine dioxide, on-site. Applicant's prior U.S. Pat. Nos. 5,171,441 and 5,122,282 disclose an apparatus and method, respectively, for treating and disinfecting water and/or wastewater. However, while these prior patents disclose a vessel containing the disinfecting solution (See Item 61, FIG. 6, U.S. Pat. Nos. 5,171,551 or 5,122,282), neither comprise an on-site generator of the disinfecting solution. Thus, the present application is an improvement of Applicant's prior U.S. Pat. Nos. 5,171,441 and 5,122,282.
Methods and/or apparatuses for treating water and/or wastewater with chlorine dioxide produced from mixing organic acids and chlorites have been described in the prior art. Callerame, in Canadian Patent No. 959,238, described a method and apparatus for producing chlorine dioxide in water. Capuano, et al., in U.S. Pat. No. 4,542,008, disclosed a process for the production of chlorine dioxide by the electrolysis of an aqueous solution of sodium chlorite. Hicks, in U.S. Pat. No. 4,590,057, disclosed a process for generating chlorine dioxide by reaction of a metal chlorite with an oxidizing agent such as gaseous chlorine. Rapson, et all, in U.S. Pat. No. 4,534,952, disclosed a chlorine dioxide generator using an inorganic acid and a solution of sodium chlorate and sodium chloride. Ratigan, in U.S. Pat. No. 4,250,144, disclosed a system for generating chlorine dioxide for disinfecting water or wastewater. Tice, et al., in U.S. Pat. No. 4,585,482, described a long-acting biocidal composition produced from a chlorine dioxide-liberating compound and an organic acid. Key, et al., in U.S. Pat. No. 4,310,425, described a system of producing chlorine dioxide for use as an anti-bacterial agent in oil field drilling fluid. Wentworth, in U.S. Pat. No. 3,082,146, described a method for the treatment of water using a residual chlorous acid concentration by mixing therewith sodium chlorite and a peroxygen compound. Alliger, in U.S. Pat. No. 4,084,747, described a germ-killing composition produced by contacting lactic acid with sodium chlorite in an aqueous media. Alcide Corporation, in International Application No. PCT/US 85/00470, described a process for disinfecting a substrate comprising a chlorine-dioxide liberating compound, such as sodium chlorite, with sufficient organic acid to lower the pH of the composition to less than about 7.
Mason, in U.S. Pat. No. 4,968,501, described a novel method of using chlorous acid to remove sulfur dioxide from exhaust combustion gases. Mason, in U.S. Pat. No. 4,801,353, described a method of bleaching wood pulp using an aqueous solution containing a salt of lactic acid and chlorous acid.
Mason, in U.S. Pat. No. 4,925,645, described a process for producing a mixture containing chlorine dioxide which comprised several steps. Mason, in U.S. Pat. No. 4,892,148, described a process of oil recovery including the steps of injecting flooding water into oil bearing subterranean formations which waters contained a mixture of salt of lactic acid and chlorous acid.
Mason, in U.S. patent application Ser. No. 07/755,825 filed Sep. 6, 1991 (which issued as U.S. Pat. No. 5,171,441), No. 07/763,185 filed Sep. 20, 1991 (which issued as U.S. Pat. No. 5,122,282), and No. 07/876,292 filed Apr. 30, 1992 described an apparatus and/or method for treating water and/or wastewater using aqueous solutions prepared from the reaction of an organic hydroxy acid or a carboxylic acid with a chlorite of an alkali metal or alkaline earth metal.